A1: ( 4 gcd 11 = 4 gcd (11 - 4) & 4 gcd (11 - 4) = 4 gcd (7 - 4) ) by PREPOWER:97;
3 gcd 4 = 3 gcd (4 - 3) by PREPOWER:97;
hence 4,11 are_coprime by A1; :: thesis: for m being Nat holds not (ArProg (4,11)) . m is Fibonacci
A2: ( ((0 * 11) + 0) mod 11 = 0 & ((5 * 11) + 0) mod 11 = 0 & ((11 * 0) + 1) mod 11 = 1 & ((11 * 8) + 1) mod 11 = 1 ) by NUMBER02:16;
then ( Fib 0, Fib (0 + 10) are_congruent_mod 11 & Fib (0 + 1), Fib ((0 + 10) + 1) are_congruent_mod 11 ) by Th7, PRE_FF:1, NAT_D:64;
then A3: for x, y being Nat st x,y are_congruent_mod 10 holds
Fib x, Fib y are_congruent_mod 11 by Th11;
for x being Nat st x < 10 holds
(Fib x) mod 11 <> 4
proof
let x be Nat; :: thesis: ( x < 10 implies (Fib x) mod 11 <> 4 )
assume A4: x < 10 ; :: thesis: (Fib x) mod 11 <> 4
A5: not not x = 0 & ... & not x = 10 by A4;
( ((0 * 11) + 2) mod 11 = 2 & ((11 * 0) + 3) mod 11 = 3 & ((0 * 11) + 5) mod 11 = 5 & ((11 * 0) + 8) mod 11 = 8 & ((1 * 11) + 2) mod 11 = 2 & ((11 * 1) + 10) mod 11 = 10 & ((3 * 11) + 1) mod 11 = 1 ) by NUMBER02:16;
hence (Fib x) mod 11 <> 4 by A5, A2, Th7, FIB_NUM2:21, FIB_NUM2:22, FIB_NUM2:23, PRE_FF:1, NUMBER06:46; :: thesis: verum
end;
hence for m being Nat holds not (ArProg (4,11)) . m is Fibonacci by A3, Th12; :: thesis: verum